local function new(r, i)
  return {r=r, i=i}
end

local function add(c1, c2)
  return {r=c1.r+ c2.r, i=c1.i + c2.i}
end

local function check(c)
  return type(c)=='table' and tonumber(c.r) and tonumber(c.i)
end

local function info(c)
  return 'real=' .. c.r ..', image=' .. c.i
end

local _M ={
  new = new,
  add = add,
  info = info
}
return _M


